We are now actively involved with the intramural effort to develop an antiviral agent for AIDS. Our initial published work has focused on the threedimensional structure determination of selected portions of the surface glycoproteins GPI20 and GP41. The work performed to date proposes possible structures for the amphipathic segments of the HIV-1 gp4l envelope protein, and may have implications for current vaccine development efforts. Our results suggest a possible mechanism for the cytopathic effects of the gpl2O-gp4l complex. We still await further experimental data from NMR or from X-ray crystallography to support further efforts in designing an antiviral agent for this potential target region.